网络URL转为Bitmap

SubTask subTask = new SubTask();
subTask.execute(iconurl);

class SubTask extends AsyncTask<String, Integer, Bitmap> {

    @Override
    protected Bitmap doInBackground(String... params) {
        try {
            String urlString = params[0];
            URL url = new URL(urlString);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            if (200 == connection.getResponseCode()) {
                InputStream inputStream = connection.getInputStream();
                //解析完毕图片对象后进行返回
                Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                return bitmap;
            }

        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Bitmap result) {



}}